OK, i'm buying a 94 z28 M6 that has a mildly built 97 ss LT1 in it from a friend. We have replaced the radiator, the hoses, the waterpump, thermostat housing gasket and intake gaskets and there is still a coolant leak from somewhere... anyone else ever had this elusive little annoyance creep up on thier LT1??? We've had like 3 other people look at it and no one can seem to find where its coming from....

Thanks !
Jeff

 

Is it running out? Or just the level in the radiaotr going low? Can you see coolant anywhere?
Could be a head gasket....

My radiator end caps leak if it gets hot enough

Sounds like you have replaced everything though...
What about:
-Banjo bolts on the back of the heads (weird coolant connectors back there)
-Do you have the factory oil cooler? Mine leaked a little from there before I removed it
-Drain plug? Its annoying but that thing can leak with a new seal no matter how tight/loose you get it.

 

I chased one of those types of leaks for several weeks. Changed cap, used a pressure tester, replaced a suspicious hose. I couldn't find anything, but the level in the radiator would go down over a couple of days. The only reason I knew to check the coolant level was because I could smell hot coolant. It turned out to be a crack in the plastic tank on the radiator. The crack would expand when it was hot, and contract when it was cold. Check around the radiator when the car is hot.

 

Ok, I'll check some of that stuff on sunday when i get back down there.. Would it be bad to add some Stop Leak to it? We havent yet..

I guess i'll have to check around to see if i can find where its running from..

Is there any type of dye or anything i can put in it and use a UV light or anything to see where its leaking from???

Jeff

 

Dont want to steal, but whats capacity of radiator and resevior on the LT1? How much should my car have in it?

 

You can get a UV kit for this. I've seen'em at PepBoys and Autozone.

 

Well, i work at autozone so i'll just grab one tonight.. I need the light and **** kit for it too right?

 

You'll need the light, dye, and glasses. I haven't seen this stuff in all Autozones, only in a few. I think all PepBoys have it.

 

well, i will probably wait until i get back to buy the kit.. we have them at my store. the little bottle is like $6 for 4oz.. plus another $15 for the light and glasses.. lol
i hate cars.. why oh why oh why do i want to be a mechanic

 

Don't use stop leak. It's a band aid at best and ususlly dosn't work. I would pressure test the system or go with the dye. But if you have no external leaks, you might have a headgasket issue. It's probably not a oil cooler issue because the oil usually ends up in the coolant because oil pressure is higher than coolant system pressure.

 

ok- well there is no milkey residue in the oil. and no oil in the coolant. its an external leak for sure and it takes about a week of driving for the coolant to be low.. not empty, just low....

 

my car had a leak that i couldnt figure out but in the end it was a cracked radiator....another note a few weeks ago she ran out of coolent at a light cause of the head gasket going soo it could be that too

 

Exact same thing happened to my 94.Finally located a vertical crack about an inch long directly under the cap,chased it for weeks before figuring it out.

 

well, the radiator is only about 9 months old.. when i bring it home i'll put a pressure tester on it and see if i can find anything, if that dont work i'll UV dye it..
Jeff

 

What kind of hose clamps do you have?
if you have the srew type the might have to go around and retighten them.
these will leak and will have a tuff time trying to find where it is comming from. you will be surprised. they do loosen up if your hoses are new.